Connecting rods have been used in every steam or internal-combustion engine (except jet and rocket engines) since such engines have been used. Connecting rods connect a piston to a throw (offset portion) of a crankshaft and convert the reciprocating motion of the piston to rotating motion of the crankshaft. Known connecting rods are typically made of forged steel or powdered iron and have a predetermined invariable length which is proportional to the piston stoke length. The connecting rod transmits the force produced by an engine piston's downward stroke (power stroke) to the crankshaft without influencing said force. The connecting rod also does not influence the force transmitted from the crankshaft to the piston, during piston's upward motion. In both cases the force exerted on one end of the connecting rod equals the force exerted on its opposite end. The connecting rod does not allow any change in crankshaft throw rotating motion diameter which is always equal to the engine piston reciprocating motion diameter.